Buffer systems for automatic firearms



Jaml7, 196 7 T. LOFFLER ETAL BUFFER SYSTEMS FOR AUTOMATIC FIREARMS FiledFeb. 16, 1965 Mr W mi k

NH 6/, 7M a E United States Patent ,27 3 Claims. 01. 89198) Theinvention relates to buffer systems for automatic firearms havingrigidly or semi-rigidly locked breech mechanisms. Such weapons generallyrequire a breech mechanism buffer which is able to absorb the surplusenergy of the recoiling breech mechanism harmlessly in order todissipate it partially or wholly or supply it to the breech mechanism onforward movement of the latter to initiate the breech closing process.The forward movement of the breech mechanism is generally effected bymeans of a helical breech closure spring which is frequently arranged ina cylindrical recess in the breech mechanism or in a part of the breechmechanism. What is described 'as surplus energy is that part of thetotal kinetic energy which is not required to compress the closurespring.

The breech mechanism buffer is generally arranged in the rear part ofthe weapon and frequently consists of compression springs, laminated cupsprings, friction springs or rubber shock absorbers. Buffers of thatkind, which have been mainly employed heretofore, have not always beensatisfactory, however, because they are rather costly to manufacture,are heavy and require an excessive amount of space to accommodate them.Pneumatic or hydraulic buffers are also known for this purpose, butthese have likewise not been successful in practice for the reasons justgiven.

The present invention provides a pneumatic buffer system which, first,renders possible the resilient absorption of the surplus energy andwhich, second, can be carried into effect in a very simple andadvantageous manner in weapons having rigidly or semi-rigidly lockedbreech mechanisms, without it being necessary to provide addition-a1parts which increase the weight of the weapon and its production costs.

The invention consists in that the cylinder of the pneumatic buffersystem is a component part of the breech mechanism or of a part of thebreech mechanism which isconnected thereto. The pneumatic buffer systemhas a piston which is advantageously supported in the rear portion ofthe weapon and extends into the cylinder which is open at the rear.

The invention has a very specially advantageous effect in the case ofthe rifle now known as the G3 rifle and rifles of similar type, since inthese rifles the breech mechanism is connected to a breech mechanismcarrier which has a cylindrical bore for receiving a breech closurespring. In these weapons, the invention can be put into effect in acompartively simple manner because parts of the weapon which are in anycase present for performing other functions, namely the breech mechanismcarrier with the closure spring tube and also the spring guiding tube,are employed as the main elements of the pneumatic buffer system. Theclosure spring tube is closed at its front end by a plug or cover andthe piston is mounted on the front end of the spring guiding tube. Inthis connection, the invention even brings a reduction in weight and, inaddition, a decrease in manufacturing costs, since the buffer heretoforeprovided in the breech or in the stock of the weapon is dispensed with.

The buffer system according to the invention can be modified in manyways. Thus, for example, one or more exhaust and suction orifices whichcan be closed by the piston may be provided in the cylinder wall, or, inmanner known per se, the piston may also be formed with a throttlingbore. These steps can be taken in each case in dependence on theparticular requirements, i.e., according to whether only a part of thekinetic energy is to be absorbed resiliently and supplied to theforwardly moving breech mechanism, or whether the surplus energy is tobe entirely dissipated.

An embodiment of the invention suitable for an automatic weapon having asemi-rigid breech mechanism will now be described in greater detail withreference to the accompanying drawing which is a side view partly insection of part of the weapon.

Reference numeral 1 designates a casing of the weapon, in which a barrelor inner or A tube 2 is fixed by means of a locking piece 3. The breechmechanism of the Weapon consists essentially of a breech mechanism head4 and a breech mechanism carrier 5 which has a tubelike extension 6positioned above the barrel 2 which is positioned in a loading tube 11fixed to the casing 1. The breech mechanism is arranged to belongitudinally slidable in the casing and, after recoiling after theshot has been fired, is brought into its forward closing position againby a closure spring 7. A guide tube 8, which is fixed in the rear partof the casing, serves to hold and guide the closure spring 7. The guidetube 8 projects through a cylindrical recess 9 in the breech mechanismcarrier 5 and into the spring tube-like extension 6. The guide tube 8carries at its forward or nozzle end a piston head 10 which is securedto the tube by means of a pin 12 and may consist with advantage of aplastics or some other suitable material. By fixing with a sealingeffect, for example screwing, a cover 13, which may likewise be madewith advantage of a plastics material, into the front end of thetube-like extension 6, the compression chamber or cylinder of apneumatic piston-cylinder assembly is created between the cover 13 andthe piston head 10. The closure spring 7 is held on the guide tube 8between a rear base plate 14 of the casing and a supporting ring 15mounted slidably on the guide tube 8, an internal shoulder 16 beingprovided in the cylindrical recess 9 and forming an abutment for thesupporting ring 15.

On recoil of the breech mechanism as a result of gas pressure occurringon firing, the closure spring 7 is compressed and at the same time airbetween the cover 13 and the piston head 10 is compressed, whereby apneumatic buffer action is obtained by the adiabatic compression of theair. The degree of the compression can be varied according to thequantity of energy to be dissipated by providing a small bore 17 in thepiston head 10 or in the cover 13. In the example shown in the drawing,a small bore 18 is also provided adjacent the forward end of extension 6in the wall thereof. Shortly before the end of the recoil of the breechmechanism, bore 18 is closed by the piston head 10, whereby at themoment of reversal of the breech mechanism a somewhat strongercompression is produced which is supplied to the then advancing breechmechanism. Furthermore, to this end, the piston may have a stud 19projecting beyond the piston and which engages in a recess 20 in theinside of the cover 13 and dimensioned in accordance with the diameterof the stud at the end of the recoil of the breech mechanism. Thesemeasures can each be employed by themselves or together.

In the example of embodiment, atmospheric air is the fluid in thepneumatic buffer system. It is also possible, however, to provide anenclosed gas in the space between cover 13 and head 10 or to supply agas to that space, for example the gas of the burnt propellent charge.The enclosed gas may be under pressure prior to movement of the pistonhead into the cylinder.

We claim:

1. An automatic firearm comprising a casing, a breech carrier mounted insaid casing and having a tube-like extension and a cylindrical recess, aguide tube secured at one end in the casing and extending through thecylindrical recess and into the tube-like extension, a piston headmounted to slide in the tube-like extension and secured at the other endin the guide tube, a supporting ring abutting on a shoulder at thejunction of the cylindrical recess and the tube-like extension tosupport the guide tube at its other end, and a coil spring around theguide tube bearing at one end against the casing and the other endagainst the supporting ring, the guide tube forming simultaneously apiston rod for a pneumatic bufier with the tube-like extension and thepiston head therein secured to the guide tube.

2. An automatic firearm according to claim 1, in which a bore isprovided in the piston head to control the degree of compression offluid in said tube-like extension.

3. An automatic firearm according. to claim 1, in which a bore isprovided in the piston head to control the degree of compression offluid in said tube-like extension, and in which at least one orifice isprovided in a wall of the tube-like extension for controlling the degreeof compression of fiuid therein, said orifice being closed by saidpiston head at a predetermined point on the travel thereof.

References Cited by the Examiner BENJAMIN A. BORCHELT, Primary Examiner.

FRED C. MATTERN, Examiner.

20 S. C. BENTLEY, Assistant Examiner.

1. AN AUTOMATIC FIREARM COMPRISING A CASING, A BREECH CARRIER MOUNTED INSAID CASING AND HAVING A TUBE-LIKE EXTENSION AND A CYLINDRICAL RECESS, AGUIDE TUBE SECURED AT ONE END IN THE CASING AND EXTENDING THROUGH THECYLINDRICAL RECESS AND INTO THE TUBE-LIKE EXTENSION, A PISTON HEADMOUNTED TO SLIDE IN THE TUBE-LIKE EXTENSION AND SECURED AT THE OTHER ENDIN THE GUIDE TUBE, A SUPPORTING RING ABUTTING ON A SHOULDER AT THEJUNCTION OF THE CYLINDRICAL RECESS AND THE TUBE-LIKE EXTENSION TOSUPPORT THE GUIDE TUBE AT ITS OTHER END, AND A COIL SPRING AROUND THEGUIDE TUBE BEARING AT ONE END AGAINST THE CASING AND THE OTHER ENDAGAINST THE SUPPORTING RING, THE GUIDE TUBE FORMING SIMULTANEOUSLY APISTON RODFOR A PNEUMATIC BUFFER WITH THE TUBE-LIKE EXTENSION AND THEPISTON HEAD THEREIN SECURED TO THE GUIDE TUBE.